This invention relates to resin compositions having antistatic characteristics. More particularly, this invention relates to resin compositions comprising an electron radiation cured product of an electron radiation curable resin precursor and an electron radiation reactive antistatic agent. In other aspects, the present invention relates to a method of making an antistatic resin composition and further to substrate sheets coated therewith. Plastics such as polyethylene, polypropylene and the like are poor conductors of electricity and have a tendency to develop and retain electrostatic charges which attract and hold dust particles. This tendency can have a detrimental effect on the appearance of the plastic, but is especially detrimental for plastic films which are used as packaging materials for delicate electronic devices, such as floppy discs for computers, or are used for hospital operating room supplies. For these kinds of uses, electrostatic charges can have a detrimental effect on the function of the plastic material. It is, of course, also well known that the build up of electrostatic charges in plastic films leads to handling and other problems in manufacturing or converting processes, especially where plastic films are transported at high speed.
One method which can be used to reduce the build up of static electricity in plastics is to add a nonreactive antistatic additive, such as a quaternary ammonium compound or carbon, when compounding the plastic matrix. The additive exudes to the surface of the plastic during processing and reduces the build up of static electricity at the surface of the plastic. This method, however, offers only short term antistatic protection. Another method for reducing static build-up involves providing a light vacuum metallized film on the plastic resin. This method, however, suffers from the disadvantage of environmental instability since the metal used to provide the conductivity characteristics is susceptible to attack by moisture and or other corrosive conditions.
Thus, it would be highly desirable to provide a resin composition having a reduced tendency to form static charges both before and after fabrication and to provide antistatic laminations comprising the resin composition. It also would be highly desirable to develop a more permanent method involving copolymerizing or cross-linking an antistatic agent with a resin to provide long lasting antistatic characteristics throughout the resin.
In accordance with the present invention, it has been found that resin compositions having desirable antistatic properties can be provided by electron radiation curing a composition comprising an electron radiation curable resin precursor and an electron radiation reactive antistatic agent. The antistatic composition can be used to coat a substrate sheet to provide an antistatic lamination. Further understanding of the present invention will be had from the following disclosure wherein all parts and percentages are by weight unless otherwise indicated.